Abstract: Hypocrelline A (HA), a light-activated pesticide, is easily degradable and low soluble in water. We used oscillatory culture method to produce HA in an aqueous solution of hydroxypropyl-β-cyclodextrin (HA-HP-β-CD) and to compare the stability of HA in ethanol water (HA-E-W), and HA-HP-β-CD, respectively, via UV spectrophotometry. Laboratory tests showed that water, oxygen, and light could promote degradation of HA, and cyclodextrin inclusion could significantly improve the inhibition rate of Valsa mali and Botryosphaeria dothidea mycelium growth and photo-thermal stability of HA. When treatment was applied at 12000 Lx of light under 26 ℃ for 10 h, the retention rates of HA in HA-supplemented ethanol solution (HA-E), HA-E-W, and HA-HP-β-CD were 92.1%, 39.0%, and 83.6% respectively. Under a reduced oxygen condition, the HA retention rate in HA-E-W reached 99.6%. While treated under dark conditions at 26 ℃ and 50 ℃ for 10 h, the retention rates of HA in HA-E-W were 94.9% and 57.1%, respectively. The retention rate of HA in HA- HP-β-CD was 95.3% after incubation in the dark for 10 h at 50 ℃. When exposed to 12000 Lx of light at 26 ℃ for 6 d, HA-HP-β-CD at a final concentration of 10 mg/L was able to suppress 93.1% and 37.3% of the mycelium growth of V. mali and B. dothidea, respectively. At the same concentration, HA-E-W suppressed 68.7% and 25.4% of the mycelium growth of both pathogens, significantly lower than those treated with HA-HP-β-CD. Data here showed that cyclodextrin is a feasible way to produce HA.